my i phone 7+ is stuck in photos - everything else is OK - can someone help a 90 yrs lady..

I'm not sure what you mean by "stuck in photos." Do you mean that the Photos app is on your screen and you can't do anything in photos and can't leave Photos for something else (i.e., the phone is frozen)? If so, see the following from If your iPhone won't turn on or is frozen - Apple Support

On your iPhone 7 or iPhone 7 Plus

1. Press and hold both the side button and the volume down button until you see the Apple logo.
2. 
3. If your phone doesn't turn on, follow these steps to check your hardware and charge your phone. You might need to charge for up to an hour.
4. If your phone still doesn't turn on, contact Apple Support.

If that isn't what you meant, please reply with details.

Try restarting the iPhone of uyou. haven't already. See the following from Restart your iPhone - Apple Support

1. Press and hold the side button until the power-off slider appears.
2. 
3. Drag the slider, then wait 30 seconds for your device to turn off. If your device is frozen or unresponsive, force restart your device.
4. To turn your device back on, press and hold the side button until you see the Apple logo.